Strip bag-producing machine



Oct. 22, 1963 E. D. NYsTRAND STRIP BAG-PRODUCING MACHINE Filed April 20. 1962 5 Sheets-Sheet l J l/JLTU Ader Oct. 22, 1963 E. D. NYsTRAND 3,107,585

STRIP BAG-PRODUCING MACHINE Filed April 20, 1962 5 Sheets-Sheet 2 Oct. 22, 1963 E. D. NYsTRAND 3,107,585

' STRIP BAG-PRODUCING MACHINE Filed April 20, 1962- 5 Sheets-Sheet 3 bczaw/Q%, Zhu/afgani w y @grafi 97 Oct. 22, 1963 E. D. NYsTRAND 3,107,585

STRIP BAG-PRODUCING MACHINE Filed April 20, 1962 5 Sheets-Sheet 4 5 Sheets-Sheet 5l hwk WW J Zw E. D. NY'sTRAND STRIP BAGPRoDuc1NG MACHINE .v o,l 0 Q NN I l l 1 lli L; l l l w www@ w59 ama Oct. 22, 1963 Filed April 2o, 1962 United States Patent O 3,107,585 STRIP BAG-FRDUCING MACHINE Ernst I). Nystrand, Green Bay, Wis., assigner to Paper Converting Machine Co., Inc., Green Bay, Wis., a corporation of Wisconsin Filed Apr. 20, 1962, Ser. No. 189,033 6 Claims. (Cl. 93-8) This invention relates to a strip bag-producing machine and method, and, more particularly, to a machine and method for producing rolls of bags longitudinally interconnected by perforation-provided bonds so that the bags can be dispensed sequentially.

A general object of the invention is to provide apparatus and a method for making rolls of thermoplastic bags out of a continuous thermoplastic web where the bags are connected along longitudinally spaced-apart lines of severance so as to permit dispensing or usage merely by unwinding the rollanalogous to the fashion contemporaneously employed for toweling, toilet tissue, etc.

Another object of the invention is to provide an apparatus and method for making bags of thermoplastic material in continuous roll form wherein the size of the bag can be readily changed and, for this purpose, a novel heatsealing arrangement is provided to transversely unite a continuous tube of thermoplastic material along longitudinally spaced-apart lines.

Still another object of the invention is to provide novel heat-sealing apparatus in which novel means are provided for relocating the heat-sealing elements which travel with a drum for thermally uniting webs of thermoplastic material traveling with the drum.

Other objects and advantages of the invention can be seen in the details of construction and :operation of the apparatus as set down in the specication hereafter.

The invention will be explained in conjunction with an illustrative embodiment in the accompanying drawing, in which:

FIG. l is a fragmentary elevational view of apparatus employed in practicing the invention;

FIG. 2 is a fragmentary elevational view of the remaining portion of the apparatus and is related to FIG. l by virtue of the designated junction line A-A in each of the two views;

FIG. 3 is an enlarged elevational view, partially in section, of the drum portion of FIG. 1;

FIG. 4 is a fragment-ary top plan view of material as it is handled by the apparatus of FIGS. 1-3;

FIG. 5 is a perspective view of the supply roll of `material employed in the sequence indicated in FIG. 4;

FIG. 6 is an enlarged fragmentary sectional view such as would be taken along the sight line 6-6 of FIG. 4;

FIG. 7 is a view similar to FIG. 6 but taken along the sight line 7--7 of FIG. 4;

FIG. 8 is a perspective view of the bag product resulting from the practice of the invention;

FIG. 9 is an enlarged fragmentary sectional view of a portion of the drum of FIG. 3 and showing the heatsealing equipment;

FIG. 10 is a view similar to FIG. 9 but upon enlarged scale;

FIG. 1l is a top plan view, partially in section and in fragmentary form, of the sealing device of FIG. l0;

FIG. 12 is an elevational view, in fragmentary form, of the sealing wire seen in FIGS. l0 and 11;

FIG. 13 is a fragmentary elevational view, partially broken away, of the drive mechanism for the drum of FIG. 3;

Y FIG. 14 is an elevational view, in fragmentary form, of the heat-sealing portion of the apparatus seen also in FIGS. 9-11;

ice

FIG. 15 is a fragmentary elevational View, partially in section, of the apparatus of FIG. 14;

FIG. 16 is a perspective view of the holder for the cross sealing wire of FIG. 12; and Y FIG. 17 is a fragment-ary sectional view of the FIG. 3 apparatus.

In the illustration given, and with particular reference to FIG. l, the numeral 10 designates generally an unwinder in which a backstand 11 rotatably supports a jumbo roll 12 of thermoplastic web material, such as polyethylene, polypropylene, etc. The roll 12 is of tubular material, as seen in exaggerated form in FIG. 5, the unwound web including two web sides 13 and 14 in more or less superposed relation. The web designated generally by the symbol W, passes through apparatus 15 in which the web W is longitudinally slit and longitudinally sealed to form a plurality of flat tubes arranged in sideby-side relation as at 15a in FIG. 4. The apparatus 15 is known to the art as a slit sealer.

From the slit sealer, the web W passes to a heat sealer generally designated 16 and then (as seen in FIG. 2) to a rewinder generally designated 17 which includes a perforator generally designated 18 and a cut-oh" roll generally designated 19. Add-itionally, the rewinder 17 includes a plurality of mandrels 201 arranged for orbital movement to provide the plurality of smaller, retail sized rolls of bag material. A suitable rewinder for this purpose may be seen in U.S. Patent No. 2,769,699, and a suitable perforator in U.S. Patent No. 2,870,840.

Focusing now on the portion of FIG. l which features the heat sealer 16, it is seen that a frame 21 is supported on the floor 22. It will be appreciated that the entire apparatus is generally symmetrical about a longitudinal center frame so that the invention can be readily appreciated from a consideration of a side elevational view. For example, the frame 21 is made up of a pair of side frames 21a suitably interconnected by means of beam members 2lb, as are the side frames '23 of the rewinder.

The side frame 21a seen in FIG. l is equipped with a pillow block 24 in which the journal 25 of drum 26 is held. The drum 26 is equipped with spider-like ends made up of arms 26a (in FIG. 3) which support the cylindrical `wallv26b. 'Ihe drum 26 is equipped with a ring gear 27 (see also FIG. 13) which provides the means for rotating the drum 26 in the pillow blocks 24.

The means for rotating the drum 26 includes a motor 28 suitably anchored to the floor 22l and a `drive pulley 29. The pulley 29 is coupled to a rst `drive belt 30 which transmits power to a driven pulley`3'1 suitably journaled in the frame 21. The pulley 31 is keyed to a shaft 32, to which is also affixed a gear 33. The gear 33 provides part of a gear train which includes a gear 34 fixed to shaft 35 and a second gear 36 also `fixed `to shaft 35. 'Bhe gear 36 engages the ring gear 27 to rotate the drum 26. The pulley 29 also is coupled to a second belt 37 which delivers power to a pulley 38 suitably journaled in the rewinder frame 17. Coupled to the pulley 33` is a gear 39 which rotates the cut-olf roll 19 and the bedroll '18a of the perforator 18. Thus, it will 'be seen that the motor 28 and drive train provide for synchronizing the rotation of drum 26 with the rewinder 17.

Heat Sealer The heat sealer 16 includes a pair of sprockets 40 (see FIG. 15),.each of which are rigidly attached to the drum 26. Entrained on each sprocket `40 is a roller chain 41 (see FIG. 14) which, at the lowest point of its travel, iS maintained under suitable tension by means of an adjustable idling sprocket assembly generally designated 42 (see FIG. 1). As is best seen in FIG. l5, each chain is equipped with a plurality of clips 43 with holders 44 bolted to axially-aligned. clips 43. Each holder 44 carries a spring 4S (see FIG. v16), and extending between the aligned `springs 45 is a sealing 'Wire 46 (see FIG. 12). The holders 44 also support bars 47 (see FIG. 10) which Contact 'the periphery of the drum 26 and maintain the wires 46 at a spaced distance from the drum Surface. Thus, it lwill be seen that the web W, in the portion of its path in which it travels with the drum 26, assumes a chordal conguration, being supported on adjacent bars 47, as seen in FIG. 9.

Each holder 441 is equipped with a brush 4S (see FIG. 14), and the brush 48 rides against a segmental commutator or slip ring 49. The slip rings 49 are connected Ito a source of electricity (not shown), and thus the wires 46 are electrically heated and operate to provide an impulse line-type seal across the Width of the 'web W, as at 46a in FIGS. 4 and 7.

In operation, the web W may be transversely heatsealed on about 15" centers, after which the perforator '18 transversely and interruptedly severs the web immediately adjacent'the linear heat-seal as at 18th in FIG. 4. After perforation, the web W passes over the main bedroll, which includes a cut-oil feature (not shown), and is rewound on one of the mandrels 2). At a predetermined point in Y is possible to produce a roll of 25, 50, 100, etc. bags arranged for sequential detachment.

The inventive construction makes it possi-ble to provide bags that can be detached immediately adjacent the linear heat-seal so that there is no unsightly bottom projection in the bag. Operating advantageously in this connection is vthe Igenerally channel-shaped bar 47 which has an angled bight portion as at 47a (see FIG. l0) to support the 'Weib in the ohordal congurat-ion previously mentioned and Where the Wire 46 is positioned at the peak of the angled bight portion 47a and insulated therefrom by Tellon tape as at 46a in FIG. l1. Teflon tape may also be used to secure the Wire 46 in position.

The bars 47 are secured by screws Sil extending into an arm port-ion 51 (see FIG. l5) of the holder 44. The holder 44 accommodates a [generally cylindrical brush retainer 52 (see FIG. 10). rIhe brush retainer has an enlarged head as at 52a (see FIG. 15), and this clamps the spring 4S against the holder 44. The spring is split at its unsecured end, as seen in FIG. 16, tor the receipt of the wire terminal bar 53 (see FIG. 12).

The springs 45 extend generally radially inwardly of the drum 26 into an annular recessed portion 26C at each end of the drum 26. From this, it will be appreciated that replacement of the Wires 46 is advantageously realized merely by removing the ends 53 from the springs 45, and removing and replacing the top layer of Tellon tape. The spacing of the linear heat-seals provided Aby the wires 46 can be changed by removing the holders 44 from their mountings on the chain clips 43. When this is done, the entire ycross assembly made up of two holders 44, two spring brackets 45, a wire 46, and a bar 47, is removed at one time and relocated according to the new length of bag to the produced.

rllhe commutator segment 49 remains tixed in place irrespective of the changed location of the wire 46, with the segments being secured to a supporting plate 54 (see FIG. 15), and hence the frame 21 by means of bolts 55.

The web W, prior to engagement with the electrically heated wires 46, passes around a driven roller 56 (see FIG. 1) which is suitably journaled in the :frame 21. After this, the -web W is maintained in place by a seal belt 57.

The roll 56 is dri-ven by means of a variable speed drive generally designated 58, deriving fpower from a gear 59 which meshes with the ring gear 27. The adjustability of speed is provided through the mechanism 60, which includes a roller 61 bearing against the belt portion of the drive 58. Moving the roller 61 changes thespeed of the roll 56, and thus controls the amount of overfeed of the web W into Ithe heat sealer. An idler roller 62 lis suitably urged against the roll 56 to ideline the entrance nip for the web W.

Advantageously, the roll 56 may be equipped with a second pulley and belt tsystem 63 for synchronizing the slitter sealer 15 with the heat sealer 16.

Referring now to FIG..17, it will be noted that the web W entering the nip dened by rolls 56 and 62 is somewhat slack, with this condition being brought about by the static bar 64. In the illustration given, the static bar is energized by a voltage of 40,000 volts D.-C., with the drum 26 being grounded. This causes the polyethylene W to assume the draped conguration seen in FIG. 13. It has also been found advantageous to provide means for relieving air carried along by the chain,

and crossbars as seen in FIG. 17. For this purpose, a supply air head-er 65 is pnovided which extends across the face of the drum 26 and which is equipped with an aspirating type outlet as at 66 Jfor ithe removal of air from just below the nip delined by the rolls 56 and 62. Thus, there is no upward lflow of air Aaccompanying the ohain and orossbars which would tend to upset the desirable draped configuration of the web W. In certaink instances, as where slitting is not utilize-d, the depression or draping of the web W as at W in FIG. 17 can be achieved through the use of an air blast, -inwhich case it is also possible to eliminate the pressurized air header 65'.

The seal belt 57 is seen to be mounted for maintaining the web W in contact with` the crossbars 47. The drive lfor this belt is designated generally in FIG. l by the numeral 67 and includes a variable speed feature as at 68 corresponding to that utilized vfor driving the web nip roll 56.

The seal belt is preferably constructed so that the thermoplastic web does not adhere to it after the heat has been removed. The belting has a high heat resistance and is non-adhesive to fthe hot polyethylene, las can be achieved through the use of silicon coatings.

The belt, in combination with the static har 64 and air blast stemming `from the outlet` 66, develops the proper slack in the web W so :that brittle and unsatisfaotorily weak seals are avoided. Tensioning of the web W during the heat sealing results in these unsatisfactory unions.

While, in the foregoing speciicat-ion, a detailed description of an embodiment of the invention has been set down in detail for the purpose of explanation thereof, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and lscope of the invention.

I claim:

l. In lapparatus for producing rolls of thermoplastic bags for tear-od usage wherein a jumbo roll of thermoplastic webs are transversely united and perforated immediately adjacent the union,

(A) a frame,

(B) a drum mounted for rotation in said frame,

(C) means for rotating said drum,

(D) `a sprocket mounted on each end of said drum for rotation therewith,

(E) an endless link chain entrained in each of said sprockets,

(F) a plurality of Wire ,holder-s releasably secured in longitudinally spaced relation on each chain. with the holders on one chain being axially aligned with the holders on the other chain,

(G) a wire connecting each aligned pair of holders,

and

(H) means on said frame for supplying electric current Ito said holders for thenmally energizing said Wires.

,2. The structure of claim l in which each holder is equipped with a spring bracket extending radially inwardly of said drum, said bracket being equipped with a bifurcated end portion for the receipt of a wire end,

aint/,ses

each of said Wires being equipped with enlarged ends.

3. The structure of claim 1 in which each holder is equipped with an inwardly-extending ann, yand a channelshaped bar extending between the `arms of aligned holders, said Wires being supported on said bars 'and out of Contact with said drum.

4. The structure of claim 1 in which each holder comprises a split housing, a brush mounted 'in said housing and securing a resilient wire-supporting bracket to said housing, and a commutator segment on said inane and 10 engageable by said brushes.

5. In apparatus for producing rolls of thermoplastic bags for tear-oli usage wherein a jumbo roll of thermoplastic Webs are transversely united and perforated irnrnediately adjacent the union,

(A) airtime,

(B) a drum mounted for rotation in said trarne,

(C) 'means for rot-ating said drum,

(D) a :sprocket mounted on each end of said drum for rotation therewith,

(E) an endless link chain entrained in each of said sprockets,

(F) a plurality `of Wire holders secured in longitudinally spaced relation on each chain, with the holiders on one chain being axially aligned lwith the holders on the other chain,

(G) a wire releasably interconnected between each pair of aligned holders, `and (H) means on said frame for supplying electric current to said holders for thermally energizing said Wires.

6. The structure of claim 5 in which each of said holders includes a spring bracket, each bracket being equipped with a mounting lslot for la Wire end, each Wire having enlarged ends for the releasable receipt thereof in a spring bracket.

Reterences Cited in the file of this patent UNITED STATES PATENTS 601,495 Comall et nl Mar. 29, 1898 2,163,278 Hayes lune 20, 1939 2,185,647 Penn et al. Ilan. 2, 194() 2,229,121 Nye et al Jan. 21, 1941 2,525,139 Ligon Oct. 1G, 1950 2,737,859 Allison et al Mar. 13, 1956 2,999,533 Slagel et al Sep-t. 12, 1961 

1. IN APPARATUS FOR PRODUCING ROLLS OF THERMOPLASTIC BAGS FOR TEAR-OFF USAGE WHEREIN A JUMBO ROLL OF THERMOPLASTIC WEBS ARE TRANSVERSELY UNITED AND PERFORATED IMMEDIATELY ADJACENT THE UNION, (A) A FRAME, (B) A DRUM MOUNTED FOR ROTATION IN SAID FRAME, (C) MEANS FOR ROTATING SAID DRUM, (D) A SPROCKET MOUNTED ON EACH END OF SAID DRUM FOR ROTATION THEREWITH, 